From time immemorial, fishermen have used floating buoys to locate fish traps and lobster pots, and to identify fishing grounds. The buoys provide rapid identification and recovery of traps or pots and means for return to the same fishing grounds.
Buoys have been hollow glass balls in a net enclosure, and hollow metal tanks, and more recently, flexible bright colored plastic buoys with a molded in eye to allow easy sighting and identification of a buoy.
The metal type buoys are often detected under poor visibility conditions employing the vessel's navigational radar. Non-metallic buoys, particularly those of plastic, do not provide any usable radar return.
It has been a practice to attach corner-type reflectors to the tops of various types of buoys, however, exposed corner reflectors are totally incompatible with the shipboard handling which can cause their damage or destruction. Likewise, an exposed corner reflector that is typically made of light sheet metal is subject to destruction by adverse weather conditions.
I have long felt that if it were possible to provide a flexible inflatable plastic buoy with an internal radar reflector, it would become possible to detect plastic buoys with radar. If properly produced and mounted, the buoy body itself can protect the corner reflector.
Typical plastic materials used are relatively transparent to radar waves with little attenuation of the radar signal. Therefore, a corner reflector within a buoy could provide an excellent radar signature. Additionally, no special precautions need be taken in the handling of the buoy on the boat or in storage.
I have been aware that the manufacture of plastic inflatable buoys using common rotational molding techniques is totally incompatible with the installation of a relatively fragile light weight metal corner reflector in the interior of a buoy.